Switch track assembly for high-speed handling of electronic components

ABSTRACT

A switch track mechanism for selectively directing electronic components from a single trackway to one of a plurality of discharge or accumulator stations comprising a first fixed track sections adjacent the trackway, a second fixed track section adjacent to and downstream of the first fixed track section, movable first and second track members operatively associated with the first and second fixed track sections and each operable between first and second limit positions. The second movable track member has a plurality of track sectors disposed in an array, a plurality of accumulator stations downstream of the second track member corresponding in number to the number of track sectors, a cartridge for electronic components is mounted at each accumulator station. The movable track sections have actuatable between limit positions whereby electronic components may be directed from the single trackway to a select one of the accumulator stations.

FIELD OF THE INVENTION

The present invention relates to broadly to new and improved method andapparatus for handling electronic components and is particularly adaptedfor the components commonly referred to as dual-in-line packages or DIPdevices. More specifically, the invention relates to a novel switchtrack arrangement for high-speed handling and separation of DIP devicesto a plurality of discharge stations.

BACKGROUND OF THE INVENTION

DIP devices of the type to which the present invention generally includea plurality of pin-like projections or leads which are relativelyfragile and have a tendency to bend or otherwise to become damagedduring handling and shipment. Such damage can distort the leads from agiven predetermined orientation necessary for proper installation into aPCB.

Method and apparatus are previously known for straightening theseelectronic components so that they are oriented properly forinstallation. The prior art lead straighteners are as described in U.S.Pat. No. 3,880,205 entitled METHOD AND APPARATUS FOR STRAIGHTENING LEADCOMPONENTS issued Apr. 29, 1975 and U.S. Pat. No. 4,481,984 entitledELECTRONIC COMPONENT LEAD STRAIGHTENING DEVICE AND METHOD issued Nov.13, 1984, owned by the assignee of the present application. Theapparatus shown in these patents operates to correct erroneousdisposition of leads and/or straighten bent leads by applying a combingaction to the leads. The assignee of the present application, also has apending application entitled HIGH-SPEED ELECTRONIC COMPONENT LEADFORMING APPARATUS AND METHOD Ser. No. 710,032, filed Mar. 11, 1985showing a system for scanning leads and also showing switching mechanismfor use in lead straightening and scanning apparatus.

While these prior apparatus were generally effective for the purposesintended, it has been found that the capacity for handling DIPs islimited. For example, in some instances, the capacity is dependent onthe cycling speed of the straightening mechanism. In other instances, itwas dependent on the configuration, arrangement and operation of thevarious feed mechanisms for delivering DIP devices through the system.In still other instances, all of the apparatus functions were performedon each DIP device delivered to the system. It has been found that someof the DIP devices in the packages do not require straightening oralignment. Accordingly, in systems where each DIP device was passedthrough a straightening or aligning apparatus, the overall speed and thequantity per time unit was limited. Furthermore, even if the systemswere discriminating, the switching mechanisms were somewhat limited.

With the foregoing in mind, it is an object of the present invention toprovide a high-speed switching apparatus for general use in DIP handlingapparatus. For example, the switching apparatus and method of thepresent invention may be utilized solely in conjunction with a scanningdevice to selectively separate DIP devices which require nostraightening or aligning operation from those which do. The switchingapparatus may also be utilized in conjunction with existing leadstraightening machines of the "300" or "600" category to thereby speedup the production rate of this equipment. It has been observed thatutilized strictly with a scanning device, the switching apparatus has acapability of directing DIP devices selectively to one of four dischargestations at a rate in excess of between 15,000 to 20,000 DIPs per hour.

SUMMARY OF THE INVENTION

Summarizing briefly, the purpose of the invention is to provide a newand novel apparatus and method for high-speed handling of DIP devicesand specifically to a novel high-speed accept/reject switchingmechanism. The switching mechanism of the present invention may beutilized as a pre-sorting unit in combination with a scanning devicesimply to separate at a high-speed rate DIPs requiring furtherstraightening or forming processing and those which do not require anyfurther processing. It may also be used and easily adapted to anexisting lead straightening system or apparatus of the type illustrated,for example, in the patents set forth above. In this conjunction, theswitching mechanism may be positioned adjacent the discharge end of anexisting trackway with or without the addition of an additional scanningdevice. Considering the basic components of the switching apparatus andsystem and with particular reference to the broad functional andoperational features thereof, the system includes, in the presentinstance, two trackway sections at the discharge end of a singletrackway emanating from a scanning device or from a lead straightenerwhich are adapted for reciprocating transverse movement between oppositelimit positions in a variety of combinations to direct DIP devicesselectively to one of four discharge stations located downstream of theswitching trackway sections. More specifically, the switching trackwaysections discharge for an array of four fixed traffic blocks which inturn communicate with an output adaptor assembly which detachablysupports four cartridges or tubes for DIPs. The operation of the entiresystem is under the control of a preprogrammed logic circuit wherein theparameters are keyed into the logic by an operator.

Describing the overall operation summarily, DIPs in cartridges are fedto an inclined trackway where they fall by gravity past a scanningstation disposed closely adjacent the high-speed switch tracing deviceof the switch tracking apparatus of the present invention. Each DIPpassing through the scanning station will be guided into one of fourcarrier tubes after the leads have been monitored by the scanning headsand the high-speed switch track activated to align the dischargetrackway with a desired discharge station via the preprogrammed logiccircuit and the parameters keyed into the logic by an operator. Forexample, station 1 may be programmed to receive DIPs requiringstraightening; station 2 may be programmed to accept DIPs which do notrequire straightening but simply alignment; and stations 3 and 4 areprogrammed to accept DIPs which do not require straightening oralignment as determined by the monitoring at the scanning station.

The apparatus includes other features facilitating a high-speedoperation. For example, the output adaptor assembly has a plurality ofindicator lamps which are normally off to indicate that a tube orcartridge for receiving DIPs is mounted in place ready to receive DIPsdelivered thereto and which will blink when the tube is filled tocapacity so that an operator can quickly replace the tube and facilitatethe high-speed operation. The lamps also blink to indicate a jamcondition. An air-operated stop pin is located upstream of the switchingtrack mechanism which is actuatable between a retracted positionpermitting flow of DIPs to the various discharge stations and a raisedposition blocking passage thereto under certain conditions as determinedby the logic circuit, for example, jamming of DIPs in the system.

Other features of the present invention include a unitary actuatormodule for the movable switch track sections which includes air operatedpiston cylinder actuators which are normally spring biased inwardlytoward a central position thereby providing a large clearance betweenthe outer terminal ends of the pistons and a stop wall in the housingwhich they confront. In this way, the switch track actuator module iseasy to assemble and remove and there are no critical clearances ortolerances which are required for accurate actuation of the switch tracksections between various limit positions which directs the DIPsselectively to one of the four discharge stations. Essentially there areonly two fastening means which hold the actuator module assembly inplace. Thus, the entire assembly is very easy to replace when desired orneeded.

The output adaptor assembly also includes a novel spring biasingarrangement for seating the cartridges firmly in place in the channelsformed therein which spring also includes a bumper element which alignswith the fixed traffic blocks guiding DIPs from the movable switchactuators to the discharge or accumulator station when a cartridge isnot in place at the discharge station to receive DIPs. Insertion of acartridge or tube into the socket of the magazine retainer sub-assemblyautomatically displaces the bumper to a position permitting flow of DIPsinto a cartridge at the discharge station.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects of the present invention and the variousfeatures and details of the operation and construction thereof arehereinafter more fully set forth with reference to the accompanyingdrawings, which:

FIG. 1 is a perspective view of a plastic DIP carrier tube, itsassociated retaining pin and a typical DIP carried within the tube;

FIG. 2 is a fragmentary plan view showing a centrally located trackwayto direct DIPs to a scanning station, closely followed by a high-speedswitch track device and an integral four tube output adaptor assemblywhereby each incoming DIP will be guided into one of the four carriertubes after its leads have been monitored by the scanning heads and thehigh speed switch track activated to the desired tube by means of thepreprogrammed logic circuits and the parameters keyed into the logic bythe operator on the operator control panels adjacent the foregoingassemblies;

FIG. 3 is an enlarged plan view of the high speed four-way switch trackassembly and its associated 4 socket output tube adaptor enclosed withinthe dot and dash box of FIG. 2 and designated FIG. 3 showing somedetails of construction of the switch track assembly;

FIG. 4 is a fragmentary view similar to FIG. 3 but showing the switchtrack actuated to deliver an incoming DIP, shown in dot and dash linesto the second tube position of the output tube adaptor assembly.Delivery of DIPs to the other tube positions is accomplished by asimilar combination of track switching as illustrated in FIGS. 3 and 4;

FIG. 5 is a fragmentary sectional elevational view taken on the lines5--5 of FIG. 3 showing additional details of construction of the outputtube holder adaptor assembly, spring biased plastic carrier tuberetaining means, microswitch carrier tube inserted or pocket emptysensing means and vertical height adjustment means to adjust the heightof the carrier tube opening into a common plane with the DIP traffictrack;

FIG. 6 is a sectional elevational view taken on the line 6--6 of FIG. 3showing additional details of construction of the switch track assembly,actuatable lower switch track plate, air cylinders and spring biasedactuators, some mounting details of the four three-way, two positionsolenoid operated air valves, module;

FIG. 7 is an end elevational view of the four socket carrier tube outputadaptor assembly taken on the line 7--7 of FIG. 3 showing additionaldetails of assembly and height adjustment means;

FIG. 8 is a bottom plan view of the switch track assembly and associatedmounting details of the associated output adaptor assembly;

FIG. 9 is a schematic view of the four 3-way 2-position solenoidoperated air valves shown as an integral module in FIG. 6, theassociated air delivery and exhaust lines, the electrical connectionstied into the logic system of the scanner (not shown) to independentlyactuate the upper or lower switch track carrier plates, the eightminiature air operated spring biased air cylinders and their actuators,one of which is shown in section; and

FIG. 10 is a schematic view similar to FIG. 9 but utilizing a moduleconsisting of two 4-way, 2 position solenoid operated air valves.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the type of electronic component for which the apparatusand method of the present invention are particularly suited and a formof cartridge C in which they are housed. These electronic componentscommonly known in the trade as dual-in-line devices are hereinafterreferred to as DIP devices. The DIPs are generally designated byreference letter D and comprise an elongated, generally rectangular bodyportion B made of a molded material such as a ceramic or plastic havingimbedded therein a plurality of leads L which ideally are uniformlyspaced and in an acceptable device are generally parallel to a planeperpendicular to their longitudinal axis. These cartridges C typicallyhave a pin or plug P which is easily removable for normally retainingthe DIP devices inside the cartridge and for permitting discharge of theDIP devices when desired simply by removing the pin either manually orby automatic means.

A general understanding of the basic structure and operation of thenovel switch mechanism will be discussed first with reference to severalof the views which best show the basic components of the apparatus andthe operation thereof such as FIGS. 2, 3 and 4. Considering now thebasic components of the apparatus in terms of function, the switchingapparatus shown in FIG. 2 comprises a main housing 10 which has aninclined front panel 12 supporting an external, elongated trackway Thaving at its upper terminal end thereof a loading station (not shown)for receiving filled cartridges C of the type illustrated in FIG. 1 forDIPS to be checked for lead straightness and alignment. The loadingstation may include a turret feed for plurality of cartridges whereinone of the DIP carry tubes is always aligned with the trackway T whilethe other DIP carrying tubes are held in reserve so that as one tube isdischarging DIPs, the other can be filled and thereafter rotated toalign with the trackway and thereby aid in high-speed processing ofDIPs. DIPs are gravity fed along the trackway T pass through a scanningstation S_(S). The switch track mechanism T_(S) located downstream ofthe scanning station S_(S) comprising two laterally movable switchtracks S_(T1) and S_(T2). These switch tracks are selectively actuatablebetween selected limit positions to direct incoming DIPs to one of, inthe present instance, four fixed discharge trackways T_(D1), T_(D2),T_(D3) and T_(D4). An output adaptor assembly A_(A) is mounted adjacentthe fixed discharge trackways and includes means for supporting thereincartridges of the type illustrated in FIG. 1.

Considering now briefly the operation of the system and with particularreferenced to FIGS. 2, 3 and 4, DIPs flow by gravity from the loadingstation along the trackway T through the scanning station S_(S) which isoperatively connected via preprogrammed logic circuits having parameterskeyed into the logic by an operator on the operator control panel P_(C)to selectively direct DIPs to one of the four discharge stations S_(D1)-S_(D4). For example, the program may call for and direct DIPs requiringa straightening operation as determined at the scanning station todischarge stations S_(D1), S_(D2) and to direct DIPs which do notrequire any straightening or aligning to discharge stations S_(D3) andS_(D4). Movement of the DIPs in this fashion is controlled by operationof the movable switch tracks S_(T1) and S_(T2) between limit positionsunder the guidance and control of the logic circuit as determined by thereadings generated at the scanning station S_(S). For example, in FIG.3, the switching tracks are actuated to limit positions operable todirect DIPs to the first discharge station S_(D1) and in this positionthe switch tracks are both actuated to the rightmost limit position. Onthe other hand in FIG. 4, the switch tracks S_(T1) and S_(T2) are in theposition to direct DIPs to the second discharge station S_(D2).

As explained in more detail below, there are other features of theswitching mechanism of the present invention including a spring biasedcarrier tube retaining means, microswitch carrier tube inserted orpocket empty sensing means and vertical height adjustment means toadjust the height of the cover tube opening so that it lies in a commonplane with the DIP traffic track.

Considering now more specifically the switch track mechanism and withparticular reference to FIGS. 4, 5 and 6, the mechanism includes aswitch track housing 20 mounted on the front panel, a fixed entrancetrack section 22 supported adjacent the upper end of the housing andadapted to be aligned with the main trackway T. The entrance tracksection 22 as illustrated has arcuate sides 24 which converge to apointed tip portion 26. An upper movable switch track 28 straddles theentrance track section 22 and is mounted in the housing for lateraltransverse movement relative thereto between opposing limit positions.The upper movable switch track section 28 comprises a pair of tracksegments or sectors 30 and 32 spaced apart and diverging outwardlyhaving confronting arcuate side walls 30a and 32a which conform to thecurvature of the arcuate side wall of the fixed entrance track sectionand operable in each limit position to form with the entrance tracksection a continuous extension of trackway T as illustrated, forexample, FIGS. 3 and 4. The switch track assembly further includes afixed lower switch track section 40 comprising as illustrated a pair ofspaced apart track segments 42, 44 equispaced from the centrallongitudinal line A--A of the trackway and each having, as illustrated,arcuate sides 42a and 44a which converges to a point of a similarconfiguration to the upper fixed entrance track section. A movable lowerswitch track section 50 comprising four track segments or sectors 52, 52and 54, 54 arranged in pairs straddle the middle fixed track sections inthe manner illustrated and in opposing limit positions define with afixed track section a continuous trackway to direct DIPs to one of thefour discharge stations. Thus, the track segments 52 have confrontingarcuate walls 52a, 52a conforming to the contour of the arcuate sides42a, 42a of the lower fixed track segments 42. Likewise the tracksections 54, 54 have confronting arcuate faces 54a, 54a conforming tothe curvature of the arcuate faces 44a of segments 44.

The limit position for the movable trackways is determined by engagementof confronting side walls of the movable track segments and the fixedtrack sections 22 and 40. (See FIGS. 3 and 4).

The movable track sections are supported for lateral transverse movementin the switch track housing and each includes a carriage supporting thetrack sectors comprising a plate member having depending legs atopposite ends which confront and are engageable by the actuator rods ofthe piston cylinder actuators. Thus, the support mechanism for the lowermovable track section 50 is best shown in FIG. 6 and includes theelongated plate 51 which slides in the gap below top plate 55 and legs57, 57 depending from opposite ends of plate 51. Note actuator rods forthe piston cylinder actuators are mounted to engage the legs and therebyeffect actuation of the movable tracks in the manner described andshown. Note also that the track sectors and fixed track elements areconfigured so that when the arcuate faces engage, the tip sectionsdefine a trackway path having generally the same width as the maintrackway T to ensure free, fast movement of DIPs through the system. Theconfiguration and mounting arrangement for upper movable track section28 is the same as that described for the lower movable track section.

A traffic block 60 is disposed below the lower track section and has, asillustrated, an upstanding central wall 62 and two outer walls 64, 64defining a pair of channel ways 66 for a series of four traffic tracks68. The traffic tracks 68, as illustrated, are in a fan-like arrayoriented and spaced in such a manner to form a continuous trackway withthe movable and fixed upper and lower switch track assemblies in themanner illustrated, for example, in FIGS. 3 and 4 and as described inmore detail below. Each traffic track 68 has an emittor-detector 69which senses when a DIP passes through the switching station and entersa cartridge at the discharge station. The emitter-detectors areoperatively connected through the logic circuit to stop pin 86 and areoperative to actuate the pin 86 to an extended position blockingmovement of DIPs to the switching station if DIPs signalled by thescanner do not pass over an emittor-detector. This arrangement,therefore, senses jamming in the system. The emitter-detectors 69 alsocount DIPs passing through the system which count is shown on digitaldisplay 71 on the front panel.

An output adaptor assembly 70 is mounted on the panel below the trafficblock 60 which has, as illustrated, four elongated channels 72 formedtherein which generally align with the traffic tracks 68. These channelsare of a configuration to support four magazines or cartridges C in thearray illustrated in FIG. 2. The output adaptor assembly 70 includes aseries of cam actuators 74 mounted within slotted openings 76. Asillustrated, the cam actuators 74 project into the slotted opening andare engagable by a cartridge when mounted therein. Each cam actuator 74is associated with a microswitch 80 which signals whether a tube orcartridge is in place or not. There are also four retention springs 82mounted in the upper wall of each slotted opening which, as illustratedin FIG. 5, bear against the inner terminal end of a cartridge C when itis seated in place. This spring functions 82 to hold the cartridges inplace. The microswitch 80 has an associated circuit board 84 which istied in with the logic circuit and which functions to permit passage ofDIP devices to a given discharge station only when a cartridge isproperly positioned in place to receive DIP devices.

The retention springs 82 are offset to define a contact point 83 remotefrom its outer free end and has a bumper 85 formed on its free end whichnormally projects into the channel to block passage of DIPs by bearingagainst traffic track 68 (FIG. 5) when the channel is empty and does nothave a cartridge for receiving DIPs. A set screw 87 is provided toselectively adjust bearing tension of leaf springs 82. Note the offsetconfiguration of the spring serves to raise bumper 85 out of the path offlow of DIPs when a cartridge is in place at the discharge station.

The output adaptor assembly 70 includes an indicator lamp 90 for eachdischarge station which is normally on when there is no tube at thestation. In the fixed entrance trackway a stop pin 86 is actuated toblock passage of DIP devices to the switch track section when a jam-upoccurs. The indicator lamps 90 change to a blinking mode when a giventube is filled to capacity to indicate to serve as indicia means for theoperator to remove a filled cartridge and replace it with an empty one.

The entire adaptor assembly 70 is actuatable vertically relative to thefixed traffic blocks to facilitate correct centering of the cartridgesor tubes and smooth flow of the DIP devices through the system to thecartridges or tubes mounted therein. Correct alignment requires that thecenter of the tube has to be in line with the traffic block in a commonplane. To this end, the entire output adaptor sub-assembly is mountedfor adjusting vertical movement on a cam bracket 92 of generallyinverted L-shaped configuration, the long leg 94 of the cam engaging ina slotted opening 96 in the switch assembly housing in the manner shownin FIGS. 5 and 7. The cam bracket 92 has an elongated slot 98 extendingfrom one face thereof which is disposed angularly relative to thehorizontal plane of the output adaptor assembly. An adjusting knob 100is mounted on support bar 102 which carries a pin 104 riding in theangled slot 98. Movement of knob 100 laterally in horizontal slot 105effects up and down movement of the adaptor assembly through pin 104 andangled slot 98. The knob 100 can be locked in place when the desiredsetting has been realized. When the output adaptor assembly is in theproper vertical position relative to the traffic tracks, DIPs movefreely from the traffic tracks to cartridges mounted in the adaptorassembly. One way of achieving this setting is by trial and error.

Means are provided for actuating the switch track assemblies betweenopposing limit positions for selectively controlling movement of the DIPdevices to one of the four discharge stations. To this end, inaccordance with the present invention, a unitary actuator moduleassembly 110 is provided which is easy to assemble in the switch trackhousing and which does not require highly precision fits or tolerancesto effect accurate displacement of the switch assemblies between thelimit positions. The actuator module as best illustrated in FIGS. 8 and9 includes an opposing pair of piston cylinders 112, 112a and 114, 114afor each switch track sub-assembly. The piston actuators 112d arenormally biased to an inner retracted position by means of an internalcoil spring such as 112c. The pistons are air-actuated to effectmovement of the switch track assembly and actuation of the cylinderscompresses the springs so that the springs return the actuators to aretracted position when pressure is exhausted.

The piston cylinder actuators are under the control of solenoid operatedcontrol valves, which in the embodiment illustrated in FIG. 9 are 3-way,2-position valves. Thus, piston cylinder actuators 112 and 112a areconnected through lines 120, 120a to valves 122, 122a. The valves asillustrated are connected to exhaust through line 124 and to an airpressure supply through line 126. Note the solenoids S₁, S₂, S₃ and S₄for the valves are operatively connected to the logic circuit throughlines 128 and 130.

Considering now briefly operation of the system and tracing specificallythe travel of DIP devices to the various discharge stations and theenergization and operation of the solenoids and valves controlling theswitching mechanisms. The actuators for the switching trackways areunder the control of the scanning unit through the preprogrammed logiccircuit for each DIP device as it passes the scanning station.Accordingly, assume that the discharge station S_(D1) is for DIPs whichrequire further processing and the DIP passing the scanner requires astraightening operation, the scanner through the logic circuit signalsde-energization of solenoids S₁, S₂, S₃ and S₄ to move switch tracksections S_(T1) and S_(T2) to the right hand limit positions so that themovable track segments lie adjacent fixed track segments 22 and 42 toestablish a continuous trackway from the fixed track section 22 to thefirst discharge station S_(T1). Note from FIG. 9 that de-energization ofsolenoids S₁, S₂, S₃ and S₄ and 122 positions the valves so that pistoncylinder and actuators 112a and 114a are connected through lines 120a toexhaust and the pressure side of the system is connected through line120 to pressurize piston cylinder actuators 112 and 114 and move thesegmental track sections to the righthandmost limit position as shown.If the scanner signals for a given DIP to be discharged to stationS_(D2), then solenoids S₃ and S₄ are energized which effects positioningof the upper trackway section to the right hand limit position and thelower trackway section to the left hand limit position.

The system illustrated schematically in FIG. 9 as viewed from the rearoperates on three-way two-position solenoid valves. FIG. 10 illustratesa modification of the present system for achieving essentially the sameoperation of the switching track sections except that only two four-way,two-position valves are used in the system. Thus, the piston cylinderactuators 112 and 112a are connected through lines 160 and 162 tosolenoid valve 164 and piston cylinder actuators 114 and 114a areconnected through lines 166 and 168 to solenoid actuator 170. Thesolenoid valves are connected through lines 172 and 174 to exhaust andare connected to an air-pressure source via line 176.

While a particular embodiment of the invention has been illustrated anddescribed herein, it is not intended to limit the invention and changesand modifications may be made therein within the scope of the followingclaims.

What is claimed is:
 1. A switch track mechanism for selectively directing electronic components from a single trackway to one of a plurality of discharge or accumulator stations comprising a first fixed track section adjacent the trackway, a second fixed track section downstream of said first fixed track section, movable first and second track members operatively associated with said first and second fixed track sections and each operable between first and second limit positions, said second movable track member having a plurality of track sectors disposed in an array, a plurality of accumulator stations downstream of said second track member corresponding in number to the number of track sectors, and means for actuating the movable track sections between limit positions whereby electronic components may be directed from the single trackway to a select one of the accumulator stations by actuation of said movable track sections to predetermined limit positions relative to one another, said first and second fixed track sections having portions confronting with portions of said movable first and second track members respectively and engageable therewith to determine said first and second limit positions.
 2. A switch track mechanism as claimed in claim 1, including a plurality of fixed track blocks corresponding in number to the number of accumulator stations positioned between the accumulator station and said second track section.
 3. A switch track mechanism as claimed in claim 2, including a sensor emitter for each of said track sectors and including a stop pin adjacent the first fixed track section operable between a raised position blocking flow of electronic components to the switch track mechanism and a lowered position and means operatively connecting the sensor emitter to serve as a means for detecting jam-up in the system.
 4. A switch track mechanism as claimed in claim 1, including an output adaptor assembly mounted downstream of the switch track sectors having a series of channels formed therein for cartridges for electronic components.
 5. A switch track mechanism as claimed in claim 4, including spring biasing means operatively positioned in said channels adapted to engage the cartridges to retain them in place and including bumper means.
 6. A switch track mechanism as claimed in claim 4, including means for selectively actuating the output adaptor assembly in a transverse direction relative to the track sectors. 